1. Field of the Inventions
The present invention relates to a remote ECG monitoring system and, more particularly, to a system for communicating ECG patient signals to monitors at convenient locations anywhere within a facility equipped with a master antenna television cable system.
2. Description of the Prior Art
Many patients in hospitals require constant monitoring of various, basic, life-support functions due to the critical nature of their physical condition. One of the most commonly monitored functions is a patient's electrocardiogram (ECG) signals and a patient in intensive care is typically equipped with a set of leads on his body and an ECG monitor right by his bedside.
In spite of the necessity for constantly watching the individual ECG monitors of all patients in an intensive care area, it is infeasible for a single nurse or trained ECG watcher to effectively watch an entire room full of monitors because of the physical space that each bed takes. Therefore, the typical solution to this problem is to provide a hard-wired connection between each ECG monitor positioned by the patient's bed and a plurality of slave monitors which are aligned in a series, in front of a console, at the nurse's station or some other convenient location. This permits a qualified nurse or ECG watcher to substantially and effectively monitor a number of patients at a single time.
Unfortunately, intensive care areas are either not large enough or too expensive to handle all patients requiring ECG monitoring. A variety of medical situations exist where doctors would like to be able to order an ECG monitor on a patient without having to subject the patient to the expense of intensive care. To achieve this, a portable monitor can be brought to the patient's room and connected to him, but now there is a problem of providing a qualified person to watch the monitor at all times. Since qualified people are very limited in number, this is an ineffective solution to the problem.
Another proposed solution is to use a form of telemetry. It has been proposed to place the ECG leads on the patient and to provide the patient with a transmitter which transmits radio waves containing the baseband ECG information. In order to receive these radio waves at a central monitoring station, it has been proposed to string antenna wires and amplifiers throughout the hospital to receive, amplify, and conduct the radio waves to the central monitoring station. Unfortunately, it is a relatively expensive procedure to modify the hospital to incorporate the antennas and amplifiers. Furthermore, because the Federal Communications Commission limits the amount of energy that may be transmitted, satisfactory performance requires substantial numbers of antennas and substantial amplification systems to derive a satisfactory signal at the receiver, and such systems provide for only a single receiver at a single location.
Still other problems exist with such a telemetry system. That is, since the patient's transmitted signal can be picked up wherever the antenna goes, it would not be possible to determine exactly where the patient is. Furthermore, the signals tend to fade in and out as the patient moves from place to place, into and out of close proximity to the antenna. Finally, if the patient is in his room and an emergency condition results, it is necessary to remove the leads from the patient and put a monitor on the patient because the existing transmitter does not have facility for a monitor.